Flood-Irrigated Rice Response to Fertilizer-Phosphorus Sources in a Phosphorus-Deficient Silt-Loam Soil

Phosphorus (P) is an essential plant macronutrient that is commonly applied as a fertilizer for optimal crop production. As the global supply of fertilizer-P sources, mainly derived from mined rock phosphate (RP), is decreasing, alternative nutrient sources need to be developed and tested, such a wastewater-recovered struvite-P materials. The objective of this greenhouse study was to evaluate below-and aboveground rice ( Oryza sativa ) response to various fertilizer-P sources [ i.e., mono-and diammonium phosphate (MAP and DAP, respectively), triple superphosphate (TSP), RP, electrochemically and chemically precipitated struvite (ECST and CPST, respectively), and an unamended control (UC) ] under flood-irrigation in a P-deficient, silt-loam soil. Of the 17 belowground properties evaluated, eight differed ( P < 0.05) among fertilizer-P sources, while three were at least numerically largest from CPST. Of the 17 aboveground properties evaluated, six differed ( P < 0.05) among fertilizer-P sources and all six were at least numerically largest from MAP or DAP. For all 22 rice properties that differed ( P < 0.05) among fertilizer-P-sources, either ECST, CPST, or both had a similar response to TSP, DAP, and/or MAP, while belowground P and calcium (Ca) and grain potassium (K) concentrations from CPST were greater ( P < 0.05) than from TSP, DAP, or MAP. Results demonstrated that struvite-P sources (i.e., ECST and CPST) are a viable, alternative fertilizer-P source, as evidenced by the large frequency of similar rice responses to other commercially available fertilizer-P sources commonly used for flood-irrigated rice production on a silt-loam soil in Arkansas (i.e., TSP, DAP, or MAP).